In browser (DevTools) mode, only non-native JS code and callbacks are reported.
Also, added "(garbage collector)" entry which accumulates samples count in GC state.
Trying to display "(compiler)" and "(external)" only brings confusion,
because it ends up in displaying scripts code under "(compiler)" node, and DOM
event handlers under "(external)" node, which looks weird.

Review URL: http://codereview.chromium.org/1523015

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4357 ce2b1a6d-e550-0410-aec6-3dcde31c8c00